A devastating house fire has claimed the lives of an 8-year-old and his baby sister.

Emergency services confirmed the two died as the result of a house fire in Burwood, Christchurch, last night.

Fire and Emergency New Zealand assistant area commander, Mike Bowden said it is believed four children and the father were inside the property when the fire started.

Three survivors have been confirmed, the father and two children.

According to a Givealittle page, a man, only identified as Des, heroically saved the lives of his two other young children and suffered injuries himself after re-entering the burning house in an attempt to save Brayden and Arianna.

Brayden was rescued by firefighters during search and rescue operations, however later passed away.

The baby, Arianna, was discovered deceased in an "unsurvivable bedroom".

Bowden said she had been in the room where the fire was most intense, and her older sibling who died was found in the doorway outside this room.

Last night, a devastating house fire claimed the lives of 8-year-old Brayden and his 9-month-old sister, Arianna. Photo / Supplied

Fire and Emergency southern fire shift manager Jill Higgison said emergency services received multiple calls about the fire just before 10.45pm on Tuesday.

Four fire crews arrived to find the single-storey home ablaze.

An unnamed neighbour said it was just "devastating".

"We heard screaming and then just all the flames, we tried to get the hose out to try and help."

The cause of the blaze is yet to be confirmed and the Fire Service believe an investigation will continue through to at least late tomorrow.

A man, and four children were in the house when the fire broke out.

Another neighbour, whose house backs on to the property, says he heard screams and cracking from flames at 10.30pm.

He quickly rushed out of bed and grabbed his garden hose, pointing it towards the burning house.

The neighbour said he heard screams from a male and children.

He also believes he saw fire crew carry a young boy out of the damaged house.

Higgison said some occupants were able to escape the blaze but two were unable to be rescued.

The Fire Service spokesman also believes fire alarms were installed at the property and can be contributed to the survival of the father and two children.

One fire crew remained at the scene overnight to monitor hot spots, and a fire investigator was due at the scene today.

A St John spokesman said two ambulances and two rapid response crews were called to the burning home.

NZ Gift of Love and Strength a Christchurch-based charity is taking donations for the family which can be dropped of at Little Explores Preschool, a local preschool.

A source who knows the family says they are "over-run" with support.